Recently, an Ad-hoc network attracts attention. In the Ad-hoc network, a plurality of wireless apparatuses is interspersed within an area and wireless apparatuses separated by a distance that does not allow direct communication therebetween can communicate with each other via another wireless apparatus. Such a network is referred to as a multi-hop networks.
As for a representative communication method of the multi-hop network, there is known a routing method (see, e.g., Japanese Patent Application Publication Nos. 2005-064721 and 2008-066861) or a flooding method.
In the case of employing the routing method, a routing table is provided for each wireless apparatus and communication takes place by determining a communication path based on the corresponding routing table.
The routing table stores communication paths to be used as numerical values. The numerical values are calculated based on, e.g., the number of hop steps to a target wireless apparatus. For example, where there are a communication path A passing through two wireless apparatuses to the target wireless apparatus and a communication path B passing through three wireless apparatuses to the target wireless apparatus, the communication path A is selected first.
On the other hand, in the case of employing the flooding method, when a wireless apparatus receives information from another wireless apparatus, the information is transmitted to neighboring wireless apparatuses by broadcast communication. By repeating such transmission/reception, the information is transferred to the target wireless apparatus.
However, in the routing method in which a communication path is determined only by the number of hop steps, even if a communication quality of the communication path deteriorates, another communication path may not be selected unless the communication is completely lost.
In the flooding method, the transmission/reception is repeated by the broadcast, so that a plurality of wireless apparatuses is in a transmission state at the same time. As a result, the amount of communication data is increased and the possibility of collision of wireless communication is increased.